iwlwifi: mvm: return -ENODATA when reading the temperature with the FW down
It seems that libsensors treats -EIO as a special non-recoverable
failure when it tries to read the temperature while the firmware is
not running. To solve that, change the error code to a milder
-ENODATA.
This fixes https://bugzilla.kernel.org/show_bug.cgi?id=196941